1. Field of the Invention
This invention relates to a heat-sensitive recording sheet and more particularly to a heat-sensitive recording sheet with improved printability.
2. Description of the Prior Art
In recent years, the heat-sensitive recording method has come to possess various advantages such that it gives almost no impact and accordingly is noiseless, development and fixation is not required and equipment maintenance is simple. Therefore, the method is widely used not only in various printers and telephone facsimile but also in many other areas.
Development of information-recording equipment has hitherto focused mainly on higher speed. Recently, however, even recording equipment with characteristics such as high resolving power and gradation is beginning to be marketed.
These characteristics can not be achieved only by improvement of recording equipment and hence heat-sensitive recording sheets having a printability compatible with the equipment become necessary. Printability of heat-sensitive recording sheets is a characteristic corresponding to the reproducibility of thermal head patterns (dots) at various printing densities. With conventional heat-sensitive recording sheets for high speed facsimiles which put emphasis mainly on thermal response, the reproducibility of dots particularly at low printing densities becomes poor and accordingly good halftone such as obtained in photooriginals can not be reproduced.